Silver Prochilodus/Flagtail Semaprochilodus taeniurus

The Flagtail Characins, genus Semaprochilodus, are some half a dozen similar-looking silver freshwater shoaling fish native to South America, from the Amazon, Orinoco and Maroni basins. Most have orange or yellow fins and tails with various degrees of black stripes. All were previously in genus Prochilodus and retain that as one of their common names.

The Silver Prochilodus, also called Silver Flagtail Characin, is native to the central Amazon Basin in Brazil. It grows to 30cm (12 inches) long. It has several dark spots on its silver body as a juvenile and retains some as an adult, especially near its tail (unlike the closely related Kissing Prochilodus which loses all its juvenile spots and is plain-bodied as an adult).

These above seem to have an irregular tail pattern and very few spots on the body.

They eat by using their lips to rasp algae off wood. They have 2 stomachs, one containing mud to help with digestion. Adults live in blackwater or clear water lakes and tributaries but migrate to whitewater rapids to spawn and return.

Although the flagtail and fins are usually orange, there is a yellow-finned morph - shown immediately above.